1. Field of the Invention
The present invention relates to hyperlink authoring and more particularly to utilizing user friendly interactive hyperlinking tools with a powerful hyperlink specification.
2. Description of the Prior Art
Although the concept of hypertext was invented many years ago, it has only become wide-spread after the advent of various document standards and powerful browsers. The hypertext approach has also been generalized to include not only textual documents but also all types of non-textual media, e.g., photo images, CAD drawings, audio, video, etc. in hypermedia applications. Typically, documents in various formats are processed and linked together so that when browsing one document, the user can quickly access related information in other parts of the same document or in other documents in different formats by simply pointing-and-clicking.
The fundamental problem of creating links on a large scale, between information contained within documents, has remained largely unsolved. Existing commercial tools are available for establishing links interactively but each link has to be created individually. These types of interactive tools are good for creating a small number of links in the documents or when the links to be created bear no discernable relationship to each other. In a publication by Peiya Liu, Ken Hampel and Arding Hsu entitled xe2x80x9cTowards Automating the Creation of Hypermedia Service Manuals by Compiling Specificationsxe2x80x9d, Proc. of Int""l Conf. on Multimedia Computing and Systems, IEEE Computing Soc. Press, 1994, pp. 203-212, the approach of using syntactic rules to automatically create a large number of related links by pattern matching algorithms was outlined. These syntactic rules can be specified using a custom-built language, called the Hyperlink Specification Language. Such a rule-based approach is good for dealing with information that is related more systematically in, for example, technical documents.
Since technical documents are highly cross-referenced and technical data can often be related by well-defined naming conventions in the industry, link specifications can be systematically created and hyperlinking can be performed automatically by parsing the link specifications. In order to provide a single format as input to the hyperlinking process, all source information is represented in SGML (Standard Generalized Markup Language). SGML is described in SGML, ISO 8879:1986 Text and Office Systemsxe2x80x94Standard Generalized Markup Language, Geneva, 1986. Textual documents are created directly with SGML editors or converted to SGML from other word processor formats. Non-textual documents such as images, drawings, video or audio are processed by Anchorable Information Unit (AIU) extractors that implement sophisticated graphics and imaging algorithms. A typical AIU specification for an object in an image specifies the coordinates of the object and some textual description of the object. The textual description can be terms such as rectangle, polygon, or possibly some higher-level terms. AIU files are also represented in SGML, similar to textual documents.
SGML is a meta-language for defining document structures which is referred to as Document Type Definition (DTD). An SGML document is an instance of its associated DTD. Conceptually speaking, the structure of an SGML document is an upside-down tree that is composed of SGML elements (or more generally, document objects). For information on the SGML syntax, refer to the publication mentioned above by Peiya Liu, Ken Hampel and Arding Hsu entitled xe2x80x9cTowards Automating the Creation of Hypermedia Service Manuals by Compiling Specificationsxe2x80x9d, Proc. of Int""l Conf. on Multimedia Computing and Systems, IEEE Computing Soc. Press, 1994, pp. 203-212. An SGML element is thus either a leaf object whose content is the actual text (or any data code) or an interior object whose content is an SGML sub-structure in addition to any possible text (or code). An SGML element is also associated with a list of attributes, e.g., id., type, name, etc. that provides additional information to characterize the element. An example of a generic manual structure is shown in FIG. 1.
However, creating specifications for hyperlinks requires knowledge of computer languages which makes it inconvenient for most authors whose main expertise is in technical writing. It is an object of the present invention to provide a solution to this problem by providing a system where the author only has to indicate an example. This example is a member of the class of objects that the user wishes to generate a link specification for.
The present invention is a system of hyperlink authoring which takes advantage of both the user-friendliness of interactive hyperlinking tools and the power of the hyperlink specification language. A software system, referred to as an Interactive Hyperlink Specification Editor (Link Editor) is included in the present invention and encapsulates this new method of hyperlink authoring. This system allows authors to establish links in multimedia documents interactively and provides generalization and specialization mechanisms for transforming the content and context of the instances of links indicated by the authors into link rules that when executed can automatically generate a large number of syntactically similar links.
With the present invention, through the link editor, the author is removed from having to possess any knowledge of the underlying hyperlink specification language. The link editor allows the authors to establish links in multimedia documents interactively and provides various mechanisms for transforming the instances of links indicated by the authors into more general link rules that apply to a large number of related links.
The link editor comprises specifications for the source, the intermediate destination, if required, and the final destination. A source document, an intermediate destination document, if required, and a final destination document is input by a user to the respective specification. Each specification comprises content pattern generalization, pattern variable instantiation, attribute modification, context specialization and attribute variable instantiation. The output of the link editor is link specifications which are provided to the automatic hyperlinker.